JP4501532B2 - Pressure-sensitive adhesive-carrying film and laminate unit manufacturing method - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive-carrying film. The pressure-sensitive adhesive-carrying film of the present invention is used as a protective film particularly in a method for producing a laminate unit for a printed circuit board including metal bump groups as interlayer connection means.

For electronic component elements such as semiconductor elements and liquid crystal display elements, the use of multilayer wiring boards has been proposed, and the use of metal bump groups as interlayer connection means between circuits formed in each layer has been proposed.
Attempts to adopt such metal bumps have been proposed as methods for improving a printed circuit board using conductive paste as an interlayer connection means, and various methods for forming bump groups by etching a copper foil have been proposed (Patent Document 1). -Patent Document 3). A printed circuit board using a metal bump group as an interlayer connection means has not been put into practical use at present, but a typical bump forming method (Patent Document 1) proposed so far is shown in FIG. And it demonstrates below along FIG. 4A to 4F and FIGS. 5G to 5J are cross-sectional views showing a conventional method of manufacturing a printed circuit board in the order of steps.

(1) Step (A):
As shown in FIG. 4A, a base substrate 91 having a three-layer structure is prepared. The base substrate 91 is formed by forming an etching barrier layer 72 made of, for example, nickel on one surface of a bump-forming metal layer (for example, copper layer) 71, for example, by plating, and conducting on the surface of the etching barrier layer 72. A circuit forming metal layer (for example, a copper layer) 73 is formed.

(2) Steps (B) to (C):
Next, as shown in FIG. 4B, a resist film 76 is selectively formed on the surface of the bump forming metal layer 71. The resist film 76 is formed so as to cover only a portion where a bump is to be formed. Subsequently, as shown in FIG. 4C, a large number of bump precursors 81 are formed by etching the bump-forming metal layer 71 using the resist film 76 as a mask material. The etching solution to be used is an etching solution that cannot erode the etching barrier layer 72 made of nickel, but can erode the bump forming metal layer 71.

(3) Steps (D) to (E):
Next, as shown in FIG. 4D, the resist film 76 used as an etching mask material in the etching is removed. FIG. 4D shows a state after the etching mask is removed. Subsequently, as shown in FIG. 4E, the etching barrier layer 72 is etched using the bump precursor 81 as a mask material. In this etching, an etching solution that does not erode the constituent metal of the bump precursor 81 but can erode the constituent metal of the etching barrier layer 72 is used. Thus, in the base material 91 having a three-layer structure, a portion 81 derived from selective etching of the bump forming metal layer (for example, copper layer) 71 and a portion 82 derived from selective etching of the etching barrier layer 72 A bump group carrier 92 having a structure in which a bump 88 made of is formed on a conductor circuit forming metal layer (for example, a copper layer) 73 is obtained.

(4) Step (F):
Subsequently, as shown in FIG. 4F, an interlayer insulating resin layer 87 is inserted into each gap of the bump 88 in the bump group carrier 92. For example, an interlayer insulating resin layer 87 made of the adhesive sheet is formed by pressing an insulating adhesive sheet onto the surface of the bump group carrier 92 on the side where the bumps 88 are formed with a heat roller. Can do. In this case, after the formation of the interlayer insulating resin layer 87, it is necessary to expose the tops of the bumps 88 by projecting from the interlayer insulating resin layer 87. If the upper portion of the bump 88 is not exposed, interlayer connection by the bump 88 cannot be reliably performed. By this step (F), an interlayer insulating resin layer 87 is formed on the conductor circuit forming copper layer 73, and the bumps 88 connected to the conductor circuit forming copper layer 73 penetrate the interlayer insulating resin layer 87. Thus, the laminate unit 93 protruding from the surface is formed.

(5) Steps (G) to (H):
Next, as shown in FIG. 5G, a metal foil for forming a conductor circuit (for example, a copper foil) is formed on the side of the laminate unit 93 where the interlayer insulating resin layer 87 is formed and the top of the bump 88 protrudes. ) 74, and as shown in FIG. 5 (H), lamination is performed by thermocompression bonding with a lamination press. Through these steps (G) to (H), the metal layers 73 and 74 formed on both main surfaces of the interlayer insulating resin layer 87 are interlayer-connected by the bumps 88, and the bumps 88 are insulated from each other. A circuit forming substrate 94 is formed. The thickness of the conductor circuit forming metal foil 74 is, for example, about 18 μm.

(6) Steps (I) to (J):
Next, as shown in FIG. 5I, a resist film 86 serving as an etching mask is formed on the surfaces of the metal layers 73 and 74, and then the metal layers 73 and 74 are etched using the resist film 86 as a mask. By doing so, the conductor circuits 83 and 84 are formed. Thus, as shown in FIG. 5J, a printed circuit board 95 in which the conductor circuits 83 and 84 on both sides are connected to each other by the bumps 88 is formed. When one of the wired circuit boards 95 and one of the laminate units 93 (see FIG. 4F) are stacked and combined, a multilayer including three layers of circuits connected by two bump groups A printed circuit board can be obtained. Furthermore, a multilayer wiring circuit board including the “n” layer circuit connected by the “n−1” layer bump group by successively laminating the above-mentioned laminate unit 93 [see FIG. 4F]. Obtainable.

JP 2001-1111189 A Japanese Patent Laid-Open No. 2001-326459 JP 2001-144212 A

The inventor has intensively studied to develop a technique for industrially embodying the conventional method of manufacturing a wired circuit board shown in FIGS. 4 and 5, and is one of the causes of defective products. In particular, it has been found that the operation in the steps (E) to (F) [see FIGS. 4 (E) to (F)] affects, and at least the steps (B) to (F) [FIG. 4 (B) to In (F)], it was found that the yield increases when a protective film having certain physical properties is used.
The present invention is based on these findings.

Therefore, the present invention
A film carrying a pressure sensitive adhesive on a support,
(I) The initial peel force after sticking to the metal layer for forming a conductor circuit is 0.05 to 30 N / 25 mm,
(Ii) The peeling force can be reduced to less than 0.05 N / 25 mm after irradiation with active energy rays,
(Iii) The logarithmic decay rate of the pressure-sensitive adhesive-carrying film by the rigid pendulum free vibration method is 200% or less of the logarithmic decay rate of the pressure-sensitive adhesive-carrying film support layer alone. The
(IV) In the temperature range exceeding the glass transition point of the support layer of the pressure-sensitive adhesive-carrying film, the logarithmic decay rate on the pressure-sensitive adhesive layer side of the film carrying the pressure-sensitive adhesive layer is Lower than the logarithmic decay rate of
(V) The support layer of the pressure-sensitive adhesive-carrying film is a polyethylene terephthalate film having a thickness of 10 to 100 μm,
(Vi) The pressure-sensitive adhesive-carrying film is characterized in that a logarithmic decay rate of the pressure-sensitive adhesive-carrying film is 0.005 to 0.07 at 23 to 180C .
According to a particularly preferred embodiment of the invention ,
( 1) (a) a metal etching barrier layer; and (b) a first conductor circuit provided on one surface of the etching barrier layer and made of a metal different from the metal constituting the etching barrier layer. A base substrate comprising: a forming metal layer; and (c) a bump forming metal layer provided on the other surface of the etching barrier layer and made of a metal different from the metal constituting the etching barrier layer. In contrast, a step of attaching a pressure-sensitive adhesive-carrying protective film to the surface of the first conductor circuit forming metal layer via the pressure-sensitive adhesive,
(2) In the base substrate, a step of forming a metal bump group by selective etching of the bump forming metal layer to obtain a bump group carrier;
(3) a step of inserting an interlayer insulating resin layer in a state where the top of each bump is exposed in the gap between the bump groups in the bump group carrier, and (4) adhesive strength of the pressure-sensitive adhesive of the protective film. In the method for producing a laminate unit for a printed circuit board, comprising the step of peeling the protective film from the surface of the metal layer for forming a conductor circuit after being reduced by irradiation with active energy rays. Used as a support protective film.
The present invention also provides:
(1) (a) a metal etching barrier layer, and (b) a first conductor circuit provided on one surface of the etching barrier layer and made of a metal different from the metal constituting the etching barrier layer. A base substrate comprising: a forming metal layer; and (c) a bump forming metal layer provided on the other surface of the etching barrier layer and made of a metal different from the metal constituting the etching barrier layer. In contrast, a step of attaching a pressure-sensitive adhesive-carrying protective film to the surface of the first conductor circuit forming metal layer via the pressure-sensitive adhesive,
(2) In the base substrate, a step of forming a metal bump group by selective etching of the bump forming metal layer to obtain a bump group carrier;
(3) inserting an interlayer insulating resin layer in a state where the top of each bump is exposed in the gap between the bump groups in the bump group carrier; and
(4) The process of peeling the said protective film from the said metal layer surface for conductor circuit formation, after reducing the adhesive force of the pressure sensitive adhesive of the said protective film by active energy ray irradiation
A method of manufacturing a laminate unit for a printed circuit board, comprising:
As the pressure-sensitive adhesive-carrying protective film,
(I) The initial peeling force after sticking to the first conductor circuit forming metal layer is 0.05 to 30 N / 25 mm,
(Ii) The peeling force can be reduced to less than 0.05 N / 25 mm after irradiation with active energy rays,
(Iii) The logarithmic decay rate of the pressure-sensitive adhesive-carrying protective film on the pressure-sensitive adhesive layer side by the rigid pendulum free vibration method is 200% of the logarithmic decay rate of the support layer alone of the pressure-sensitive adhesive-carrying protective film. And
(IV) In the temperature range exceeding the glass transition point of the support layer of the pressure-sensitive adhesive-carrying protective film, the logarithmic decay rate of the pressure-sensitive adhesive layer side of the protective film carrying the pressure-sensitive adhesive layer is Lower than the logarithmic decay rate of the layer alone,
(V) The support layer of the pressure-sensitive adhesive-carrying protective film is a polyethylene terephthalate film having a thickness of 10 to 100 μm,
(Vi) The logarithmic decay rate of the pressure-sensitive adhesive-carrying protective film is 0.005 to 0.07 at 23 to 180 ° C.
Use pressure-sensitive adhesive-carrying protective film
The present invention relates to a method for manufacturing a multilayer unit for a printed circuit board.

  When the pressure-sensitive adhesive-carrying film of the present invention is used as a protective film in a method for producing a laminate unit for a printed circuit board, the protective film is attached on one surface of the base substrate, and the etching step and the interlayer Since the insulating resin layer insertion step can be carried out, the transport and workability of those steps are improved, and in the etching step, the circuit forming metal layer can be protected from the etching solution, In the inter-layer insulating resin layer insertion step, the inter-layer insulating resin layer can be inserted into the gap between the bump groups while maintaining an excellent upright state of the bump groups.

  Since the pressure-sensitive adhesive-carrying film according to the present invention has specific physical properties as described above, it can exhibit an excellent effect when used as a protective film in the method for producing a laminate unit for a printed circuit board. First, a method for producing a laminate unit for a printed circuit board using the pressure-sensitive adhesive-carrying film of the present invention as a pressure-sensitive adhesive-carrying protective film will be described, followed by the pressure-sensitive adhesive of the present invention. The structure of the carrier film will be described.

(I) 1st manufacturing method of the laminated body unit for printed circuit boards using this invention film A 1st manufacturing method is demonstrated in order below along FIG.1 and FIG.2.
(1) Step (A):
As shown in FIG. 1A, a base material 31 having a three-layer structure is prepared. The base substrate 31 is formed by forming an etching barrier layer 12 made of, for example, nickel on one surface of a bump forming metal layer (for example, a copper layer) 11 by, for example, plating, and conducting on the surface of the etching barrier layer 12. A circuit forming metal layer (for example, a copper layer) 13 is formed. The thickness of the bump forming metal layer 11 is, for example, about 3 to 100 μm, the thickness of the etching barrier layer 12 is, for example, about 2 μm, and the thickness of the conductive circuit forming metal layer is, for example, about 3 to 50 μm. It is. In the method using the film of the present invention, the film according to the present invention is stuck as the pressure-sensitive adhesive-carrying protective film 17 on the surface of the metal layer 13 for forming the conductor circuit of the base substrate 31. The protective film 17 has a pressure-sensitive adhesive layer 19 on one surface of the support 18, and is attached to the surface of the conductive circuit forming metal layer 13 via the pressure-sensitive adhesive layer 19. To do.

(2) Steps (B) to (C):
Next, as shown in FIG. 1B, a resist film 16 is selectively formed on the surface of the bump forming metal layer 11. The resist film 16 is formed so as to cover only a portion where a bump is to be formed. Subsequently, as shown in FIG. 1C, a large number of bump precursors 21 are formed by etching the bump forming metal layer 11 using the resist film 16 as a mask material. This etching can be performed by, for example, wet etching, and the etching solution used cannot etch the etching barrier layer 12 made of, for example, nickel, but can etch the bump forming metal layer 11. It is a liquid.

(3) Steps (D) to (E):
Next, as shown in FIG. 1D, the resist film 16 used as an etching mask material in the etching is removed. FIG. 1D shows a state after the etching mask is removed. Subsequently, as shown in FIG. 1E, the etching barrier layer 12 is etched using the bump precursor 21 as a mask material. In this etching, an etching solution that does not attack the constituent metal of the bump precursor 21 but can attack the constituent metal of the etching barrier layer 12 is used. For example, when the bump precursor 21 is made of a copper layer and the etching barrier layer 12 is made of nickel, a nickel stripping solution is used. Thus, in the base material 31 having a three-layer structure, a portion 21 derived from selective etching of the bump forming metal layer (for example, copper layer) 11 and a portion 22 derived from selective etching of the etching barrier layer 12 A bump group carrier 32 having a structure in which a bump 28 made of is formed on a conductor circuit forming metal layer (for example, a copper layer) 13 is formed on the protective film 17.

(4) Step (F):
Subsequently, as shown in FIG. 1 (F), an interlayer insulating resin layer 27 is inserted into the respective gaps of the bumps 28 in the bump group carrier 32. For example, the interlayer insulating resin layer 27 made of the adhesive sheet is formed by pressing an insulating adhesive sheet onto the surface of the bump group carrier 32 on the side where the bumps 28 are formed with a heat roller. Can do. At this time, after the formation of the interlayer insulating resin layer 27, it is necessary to expose the tops of the bumps 28 by projecting from the interlayer insulating resin layer 27. Therefore, as the adhesive sheet, a sheet that is appropriately thinner than the height of the bump 28 is used. If the upper portion of the bump 28 is not exposed, interlayer connection by the bump 28 cannot be reliably performed. By this step (F), an interlayer insulating resin layer 27 is formed on the conductor circuit forming copper layer 13, and the bumps 28 connected to the conductor circuit forming copper layer 13 penetrate the interlayer insulating resin layer 27. Then, the laminate unit 33 protruding from the surface is formed on the protective film 17.

(5) Steps (G) to (I):
Next, as shown in FIGS. 2G to 2I, the protective film 17 attached to the laminate unit 33 is peeled from the laminate unit 33. In the embodiment shown in FIGS. 1 and 2, an active energy (for example, ultraviolet ray or electron beam) curable adhesive is used as the adhesive of the pressure-sensitive adhesive layer 19, as shown by an arrow A in FIG. After irradiating active energy (for example, an ultraviolet ray or an electron beam) from the support 18 side to reduce the adhesive force of the pressure-sensitive adhesive layer 19, as shown in FIG. 17 is peeled from the laminate unit 33. In this case, the support 18 needs to be able to transmit active energy (for example, ultraviolet rays or electron beams). By peeling off the protective film 17 from the laminate unit 33, the laminate unit 33 can be obtained as shown in FIG. Using this laminate unit 33, a circuit forming substrate 34 [FIG. 2 (K)] or a wiring circuit substrate 35 [FIG. 2 (M)] is manufactured as will be described later, and further a multilayer wiring circuit substrate is manufactured. can do.

(6) Steps (J) to (K):
In order to manufacture the circuit forming substrate 34 as shown in FIG. 2 (K) using the laminate unit 33 thus obtained, as shown in FIG. 2 (J), the conductor circuit forming metal foil 14a and The laminate unit 33 is thermocompression bonded with a laminate press. At this time, the conductive circuit forming metal foil 14 a is joined to the protruding top portions of the bumps 28 in the multilayer unit 33. In the circuit forming substrate 34 thus obtained, the first conductor circuit forming metal layer 13 and the second conductor circuit forming metal layer 14 are electrically connected via the bumps 28. The interlayer insulating resin layer 27 is in an electrically insulated state. In addition, the thickness of the metal foil 14 for conductor circuit formation is about 3-50 micrometers, for example.

(7) Steps (L) to (M):
As shown in FIG. 2L, an etching mask is formed on each surface of the first conductor circuit forming metal layer 13 and the second conductor circuit forming metal layer 14 of the circuit forming substrate 34 obtained in the step (K). Then, the first conductor circuit forming metal layer 13 and the second conductor circuit forming metal layer 14 are etched using the resist film 16 as a mask, thereby forming conductor circuits 23 and 24. Can be formed. The resist film 16 is removed, and a printed circuit board 35 is formed as shown in FIG. The printed circuit board 35 has a first conductor circuit 23 on one surface and a second conductor circuit 24 on the other surface, and is electrically connected via bumps 28 at portions where these circuits are necessary. In addition, the bumps 28 are electrically insulated from each other by the interlayer insulating resin layer 27.

(II) Second Manufacturing Method of Laminate Unit for Printed Circuit Board Using the Film of the Present Invention Next, a second manufacturing method using the film of the present invention will be described with reference to FIG. In this second manufacturing method, a bump group is formed from the bump forming metal layer by the same steps as steps (A) to (D) of the first manufacturing method, and then the step (E) of the first manufacturing method. (Ie, without performing etching of the etching barrier layer), the following steps (F) and subsequent steps are performed.
(1) Step (A):
In the second manufacturing method, bumps 21 are formed by the same method as steps (A) to (D) in the first manufacturing method (I) [see FIGS. 1 (A) to (D)]. That is, a group of bumps 21 derived from the selective etching of the bump forming metal layer (for example, copper layer) 11 is formed on the etching barrier layer 12 and the conductor circuit forming metal layer (for example, copper layer) 13. A bump group carrier 32 having the above structure is formed on the protective film 17. FIG. 3A shows this state.

(2) Step (B):
Next, without carrying out the step (E) in the first manufacturing method [that is, without carrying out the etching of the etching barrier layer 22], as shown in FIG. An interlayer insulating resin layer 27 is inserted into each gap of the bump 21 in the body 32. For example, the interlayer insulating resin layer 27 made of the adhesive sheet is formed by pressing an insulating adhesive sheet onto the surface of the bump group carrier 32 on the side where the bumps 21 are formed with a heat roller. Can do. At this time, after the formation of the interlayer insulating resin layer 27, it is necessary to expose the top of the bump 21 from the interlayer insulating resin layer 27 so as to be exposed. Therefore, as the adhesive sheet, a sheet that is appropriately thinner than the height of the bump 21 is used. If the upper portion of the bump 21 is not exposed, interlayer connection by the bump 21 cannot be reliably performed. By this step (B), an interlayer insulating resin layer 27 is formed on the conductor circuit forming copper layer 13, and the bumps 21 connected to the conductor circuit forming copper layer 13 penetrate the interlayer insulating resin layer 27. And the laminated body unit 33 protruded from the surface is formed on the protective film 17 by this invention.
The multilayer unit for a printed circuit board obtained by the second manufacturing method includes the etching barrier layer 22 in an unetched state. As will be described later, the second conductor circuit forming metal is included. When the layer 14 is selectively etched, the etching barrier layer 22 is simultaneously etched.

(3) Steps (C) to (D):
Next, as shown in FIGS. 3C to 3D, the protective film 17 according to the present invention attached to the laminate unit 33 is peeled from the laminate unit 33. As in the first manufacturing method, an active energy (for example, ultraviolet ray or electron beam) curable adhesive is used as an adhesive for the pressure-sensitive adhesive layer 19, as indicated by an arrow A in FIG. The adhesive energy of the pressure-sensitive adhesive layer 19 is reduced by irradiating active energy (for example, ultraviolet light or electron beam) from the side of the support 18 that can transmit active energy (for example, ultraviolet light or electron beam). From FIG. 3D, the protective film 17 is peeled off from the laminate unit 33. By peeling off the protective film 17 from the laminate unit 33, the laminate unit 33 can be obtained.

(4) Step (E):
Using the laminate unit 33, the metal foil for forming a conductor circuit and the laminate unit 33 are heated by a laminate press in the same manner as the steps (J) to (K) of the first manufacturing method. A circuit forming substrate 34 as shown in FIG. 3E can be manufactured by pressure bonding. In the circuit forming substrate 34 thus obtained, the first conductor circuit forming metal layer 13 and the etching barrier layer 12 are electrically connected to the second conductor circuit forming metal layer 14 via the bumps 21. The bumps 21 are electrically insulated from each other by the interlayer insulating resin layer 27.

(5) Steps (F) to (G):
As shown in FIG. 3F, an etching mask is formed on each surface of the first conductor circuit forming metal layer 13 and the second conductor circuit forming metal layer 14 of the circuit forming substrate 34 obtained in the step (E). A resist film 16 is formed, and then etching is performed using the resist film 16 as a mask. At this time, the conductor circuit 23 (22) can be formed by simultaneously etching the first conductor circuit forming metal layer 13 and the etching barrier layer 12 on one surface. Also, the conductor circuit 24 can be formed on the other surface by etching the second conductor circuit forming metal layer 14. As an etchant, an etchant that can simultaneously etch a metal (for example, copper) that forms the first conductor circuit forming metal layer 13 and a metal (for example, nickel) that forms the etching barrier layer 12. Is used. Subsequently, when the resist film 16 is removed, a printed circuit board 35 is formed as shown in FIG. The printed circuit board 35 has a first conductor circuit 23 (22) on one surface and a second conductor circuit 24 on the other surface, and the bumps 21 are interposed in portions where these circuits are necessary. In addition, the bumps 21 are electrically insulated from each other by the interlayer insulating resin layer 27.
In this second manufacturing method, the etching barrier layer 12 and the first conductor circuit forming metal layer 13 are both removed by one selective etching using the same resist film 16 as a mask. Using this as a mask, the etching barrier layer 12 does not need to be selectively removed, which is advantageous in that the number of steps is reduced.

(III) Protective film Next, the pressure-sensitive adhesive-carrying film according to the present invention will be described.
(1) Support As shown in FIGS. 1 to 3, the pressure-sensitive adhesive-carrying protective film 17 of the present invention has a pressure-sensitive adhesive layer 19 on one surface of a support 18. As this support, any synthetic resin film can be used as long as the pressure-sensitive adhesive can be supported, and it is preferable to have etching resistance. As such a synthetic resin, a polyester such as polyethylene terephthalate or polyethylene naphthalate, or a polyolefin such as polyimide, polyphenylene sulfide, polyvinyl chloride, or polypropylene can be preferably used. Although not particularly limited, the synthetic resin film may be annealed to improve dimensional stability at high temperatures. When an active energy curable adhesive (for example, an ultraviolet ray or an electron beam curable adhesive) is used as the pressure sensitive adhesive, a support capable of transmitting active energy (for example, an ultraviolet ray or an electron beam) should be used. is required.

  The thickness of the support is not particularly limited, but does not adversely affect the workability of the base substrate 31, the bump group carrier 32, or the laminate unit 33 shown in FIGS. The thickness is preferably such that the metal layer for forming a conductor circuit can be sufficiently protected, for example, 100 μm or less, preferably 75 μm or less, and more preferably 50 μm or less. On the other hand, the lower limit of the thickness of the support is not particularly limited, but is 10 μm, for example. When the thickness of the support exceeds 100 μm, flexibility when used as a protective film is impaired, and in the protective film peeling process, peeling may be difficult, and the laminate unit may be bent or bent, and less than 10 μm. If it becomes, it will be easy to produce a deformation | transformation and bending at the time of using as a protective film.

(2) Pressure-sensitive adhesive The pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer preferably has removability, and, for example, adhesive strength is reduced by irradiation with active energy (for example, irradiation with ultraviolet rays or electron beams). It is a pressure sensitive adhesive. Specifically, an elastomer polymer such as a known active energy curable acrylic resin, silicone resin, epoxy resin, styrene-butadiene, SBS or SIS, isoprene, chloroprene, or acrylic butadiene, An adhesive such as natural rubber or recycled rubber can be used. In particular, an acrylic resin pressure sensitive adhesive is preferable. If necessary, a tackifier such as a polyterpene resin, gum rosin, rosin ester or rosin derivative, oil-soluble phenol resin, coumarone-indene resin, or petroleum hydrocarbon resin can be blended. In addition, any type of pressure-sensitive adhesive such as a solvent type, an emulsion type, or a solventless type can be used.

  The initial peel force after application of the pressure-sensitive adhesive is preferably 0.05 to 30 N / 25 mm, more preferably 0.1 to 10 N / 25 mm. If the initial peel force exceeds 30 N / 25 mm, it becomes difficult to make the peel force after the adhesive strength reduction treatment less than 0.05 N / 25 mm, and if the initial peel force is less than 0.05 N / 25 mm, the adhesive force is insufficient. In some cases, the peeling process may be performed before the peeling process is performed. On the other hand, the peel strength after the adhesive strength reduction treatment is preferably less than 0.05 N / 25 mm. If the peeling force after the adhesive strength reduction treatment is 0.05 N / 25 mm or more, the laminate unit may be bent or bent during the peeling operation. In this specification, “peeling force” means a value measured according to JIS Z0237. The “initial peel force” means a peel force within 20 minutes after the sticking process.

  The thickness of the pressure-sensitive adhesive layer is not particularly limited as long as it is a thickness that can express the above-mentioned peeling force after the initial peeling force and the adhesive strength reduction treatment. Specifically, although it varies depending on the type of pressure-sensitive adhesive to be used, it is preferably 0.5 to 20 μm, more preferably 0.5 to 10 μm. If the thickness of the pressure-sensitive adhesive layer exceeds 20 μm, the fluidity of the pressure-sensitive adhesive layer cannot be ignored, and when used as a protective film, when the formed bump is inserted into the interlayer insulating resin layer If the thickness is less than 0.5 μm, the pressure-sensitive adhesive may have insufficient adhesive strength and may be peeled off before the peeling process is performed.

(3) Logarithmic damping factor As a result of further examination by the inventor regarding physical properties when the pressure-sensitive adhesive-carrying film of the present invention is used as a protective film in a method for producing a laminate unit for a printed circuit board, rigid pendulum free vibration The logarithmic decay rate on the pressure-sensitive adhesive layer side (before the adhesive strength reduction treatment) of the protective film according to the method is 200% or less of the logarithmic decay rate of the support layer alone (hereinafter referred to as logarithmic decay rate ratio). Preferably, it is more preferably 150% or less, and it has been found that it is particularly preferably 100% or less in the temperature range exceeding the glass transition point of the support layer.

In this specification, the “logarithmic decay rate” is a value measured by a rigid pendulum free vibration method. A specific method for measuring the logarithmic attenuation rate by the rigid pendulum free vibration method will be described with reference to FIG. FIG. 6 is a schematic explanatory view of the rigid pendulum type physical property tester 41, which has a sample placement unit 43 on the cooling table 42. The cooling table 42 can control the temperature of the sample 47. For example, the low temperature range can be accurately controlled by liquid nitrogen and the high temperature range can be accurately controlled by a heater. When the logarithmic decay rate on the pressure-sensitive adhesive layer side of the film sample 47 carrying the pressure-sensitive adhesive layer 49 on the support 48 is measured by the rigid pendulum type physical property tester 41, it is shown in FIG. as placed into contact with the side of the support 48 of the film sample 4 7 sample placing portion 43, place the cylinder edge 44 on the pressure-sensitive adhesive layer 49.

  The cylinder edge 44 can be rotated over a small distance by rotating on the pressure-sensitive adhesive layer 49 as indicated by an arrow R2 by a pendulum (not shown) capable of reciprocating movement of the arrow R1. At this time, the damping action occurs in the vibration period of the pendulum due to the viscoelasticity of the pressure-sensitive adhesive, and the vibration period and the logarithmic attenuation rate can be measured over time. When measuring the logarithmic decay rate of the support layer alone, the logarithmic decay rate can be measured in the same manner as described above by placing only the support on the sample mounting portion 43.

Specifically, the logarithmic decay rate (Δ) is calculated by the following calculation formula (1):
Δ = −ln (Yr) (1)
Can be calculated. Here, Yr is a calculation formula (2):
Yr = (Tpy3-Tpyav) / (Tpy1-Tpyav) (2)
Tpyav is calculated from Equation (3):
Tpyav = (Tpy1 + 2 × Tpy2 + Tpy3) / 4 (3)
Is calculated from Further, Tpy1, Tpy2, and Tpy3 are respective local maximum values as shown in FIG. 7 which is a graph of the relationship between the pendulum amplitude and the passage of time.

  Now, when the logarithmic decay rate of the synthetic resin film alone is measured at a high temperature using a rigid pendulum type physical property tester as shown in FIG. 6, the logarithmic decay rate is almost below the glass transition temperature (Tg) of the synthetic resin. There is no change or a slight increase is observed. As the temperature rises, the logarithmic decay rate rises relatively abruptly around the glass transition temperature (Tg), and when the temperature rises further, the raised logarithmic decay rate is maintained as it is. This phenomenon is considered to be due to softening of the synthetic resin near the glass transition temperature.

  When a pressure-sensitive adhesive is applied to a synthetic resin film and the logarithmic decay rate is measured from the pressure-sensitive adhesive layer side at an elevated temperature as shown in FIG. 6, a similar tendency should be observed. . However, according to what the present inventors have found, an increase in the logarithmic decay rate may be suppressed when a pressure-sensitive adhesive is applied. That is, in a specific temperature range exceeding the glass transition point of the support layer, the logarithmic decay rate on the pressure-sensitive adhesive layer side of the protective sheet carrying the pressure-sensitive adhesive layer is larger than the logarithmic decay rate of the support layer alone. The phenomenon of lowering is observed at least in the range where the thickness of the support layer is 10 to 100 μm (more preferably 10 to 50 μm) and the thickness of the pressure-sensitive adhesive layer is 0.5 to 5 μm. The present inventor has confirmed. Moreover, when a laminate unit is manufactured using a protective sheet having such physical properties, the yield of a printed circuit board or a multilayer printed circuit board manufactured from these laminate units can be improved.

The reason why the increase in the logarithmic decay rate is suppressed when a pressure-sensitive adhesive is applied is currently unknown, but using a pressure-sensitive adhesive-carrying film exhibiting such physical properties as a protective sheet, for example, The reason why a laminate unit providing an excellent yield can be estimated as follows when the laminate unit for a printed circuit board is manufactured by the method shown in FIGS.
For example, the bump group carrier 32 shown in FIG. 1 or the like has a structure in which a large number of bumps 28 are carried on the conductor circuit forming metal layer 13. Here, the layer thickness of the conductor circuit forming metal layer 13 is, for example, 3 to 50 μm, and the height of the bump 28 is, for example, 30 to 100 μm. Therefore, the bump group carrier 32 has a relatively high bump group on the relatively thin metal layer 13 for forming a conductor circuit, and the bump 28 is used for forming the first and second conductor circuits. Since the connection between the metal layers is formed only in a portion where connection is necessary, the metal layers are unevenly distributed. In the step of inserting the interlayer insulating resin layer 27 into the bump group carrier 32, when the bump group carrier is pierced into the insulating resin sheet, if the protective sheet 17 is too soft, a part of the bump group becomes a conductor. When the bumps are pushed into the protective sheet 17 side through the circuit-forming metal layer 13 and the bumps are not evenly projected, or the bump tips pierce the insulating resin sheet, It is thought that it will shift. If a laminate unit in which such a deviation occurs is used, a connection failure or a connection position between the first and second conductor circuit forming metal layers may be shifted.

  The temperature at which the interlayer insulating resin layer insertion step is performed is in the range of room temperature to about 120 ° C., and the temperature range corresponds to the vicinity of the glass transition temperature of the synthetic resin constituting the support 18 of the protective sheet 17. When the logarithmic decay rate of the protective sheet 17 is larger than 200% of the logarithmic decay rate of the support 18 during the interlayer insulating resin layer insertion step, the probability that the deviation of the bump will occur increases.

  On the other hand, when a protective sheet having a logarithmic attenuation factor exhibiting the above-described physical properties is used, moderate rigidity is imparted to the protective sheet, and an increase in the logarithmic attenuation factor in the vicinity of the execution temperature of the interlayer insulating resin layer insertion process is prevented. A constant logarithmic decay rate can be maintained. Therefore, it can be presumed that a laminate unit providing an excellent yield can be obtained. The present invention is not limited by the above estimation.

  Therefore, when the pressure-sensitive adhesive-carrying film according to the present invention is used as a protective film in the method for manufacturing a laminated unit for a printed circuit board shown in FIGS. / 25 mm, the peel strength after the adhesive strength reduction treatment is less than 0.05 N / 25 mm, the thickness of the support layer is 10 to 100 μm, and the thickness of the pressure sensitive adhesive is 0.5 to 20 μm. , A protective film (hereinafter referred to as ultrathin film) having a logarithmic damping factor of 200% or less of the logarithmic damping factor of the support layer alone (on the pressure-sensitive adhesive layer side of the protective sheet by the rigid pendulum free vibration method) (Referred to as a protective film).

  In the temperature range below the glass transition point of the synthetic resin constituting the support layer, the logarithmic decay rate of the ultrathin protective film is logarithmic decay on the pressure-sensitive adhesive layer side of the protective sheet (before the adhesive strength reduction treatment). The rate is preferably 70 to 200%, and more preferably 70 to 150% of the logarithmic decay rate of the support layer alone. Further, in a temperature region exceeding the glass transition point of the synthetic resin constituting the support layer (for example, the glass transition point or 180 ° C. region), the pressure-sensitive adhesive layer side of the protective sheet (before the adhesive strength reduction treatment) The logarithmic decay rate is preferably 200% or less of the logarithmic decay rate of the support layer alone, more preferably 150% or less, and particularly preferably 100% or less. The logarithmic decay rate of the ultrathin protective film is preferably 0.005 to 0.07, more preferably 0.005 to 0.06 at 23 to 180 ° C.

  The thickness of the pressure-sensitive adhesive layer of the ultrathin protective film is preferably 0.5 to 20 μm, more preferably 0.5 to 10 μm. Further, as the pressure sensitive adhesive, for example, an ultraviolet curable acrylic adhesive is preferably used, and as the support, for example, polyethylene terephthalate is preferably used.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but these do not limit the scope of the present invention.

Example 1
(1) Production of printed circuit board 35 In the method shown in FIGS. 1 and 2, the printed circuit board 35 was produced using the pressure-sensitive adhesive-carrying film according to the present invention as the protective film 17. As the base substrate 31, a substrate having a nickel plating etching barrier layer 12 on one surface of the bump forming copper layer 11 and a conductor circuit forming copper layer 13 formed on the surface of the etching barrier layer 12 is used. It was. The bump forming copper layer 11 had a thickness of 100 μm, the etching barrier layer 12 had a thickness of 2 μm, and the conductor circuit forming copper layer had a thickness of 18 μm. As the protective film 17 according to the present invention, an ultra-thin acrylic adhesive layer (layer thickness = 2 μm) as an adhesive layer 19 is provided on a polyethylene terephthalate sheet (thickness = 25 μm) as a support 18. A protective film was used.

  The bump forming copper layer 11 and the etching barrier layer 12 were etched by a conventional method to obtain a bump group carrier 32. Then, the application | coating process of the electrically conductive paste was abbreviate | omitted, and the bump group support body 32 was stabbed into the polyimide resin sheet, and the laminated body unit 33 was obtained. This step was performed at about 100 ° C. Subsequently, the protective film 17 is irradiated with ultraviolet rays, the protective film 17 is peeled off, the conductor circuit forming metal foil 14a and the laminate unit 33 are thermocompression-bonded by a laminating press, and a printed circuit board is formed by a conventional method. 35 was produced. The yield of the printed circuit board 35 was 100%. The yield of the printed circuit board here is not economical unless it is 100%, and the yield of 90% or less is practically unusable.

(2) Measurement of peel strength of protective film The peel strength of the ultrathin protective film according to the present invention used in Example 1 (1) was measured by the following method.
(A) Initial peeling force A sample obtained by cutting an ultrathin protective film into a size of 25 mm in width and 220 mm in length is pasted on a metal surface for forming a conductor circuit whose surface is washed so that the pasting area is 25 mm × 100 mm. Then, a rubber roll having a weight of 2 kg was reciprocated once to make a test piece, and the test piece was left under the conditions of JIS Z0237 for 20 minutes, and the adhesive strength was measured by peeling in a 180 ° peel direction in accordance with JIS Z0237. . The results are shown in Table 1.
(B) Peeling force after irradiation with active energy rays The test piece prepared in the same manner as in Example 1 (2) (a) was allowed to stand for 20 minutes under the conditions of JIS Z0237 and irradiated with ultraviolet rays of 400 mJ / cm ² . Thereafter, the adhesive strength was measured by peeling in a 180 ° peel direction in accordance with JIS Z0237. The results are shown in Table 1.

(3) Measurement of logarithmic decay rate of protective film The logarithmic decay rate of the ultrathin protective film according to the present invention used in Example 1 (1) was measured by the method shown in FIG. As a measuring device, a rigid pendulum type physical property tester RPT-3000W (manufactured by A & D Co.) was used. The temperature was raised from 23 ° C. to 180 ° C. at a rate of 4 ° C./60 seconds, and the amplitude attenuation was measured without changing the wavelength of the pendulum. The measurement results are shown in FIG.
On the other hand, the result of having measured the logarithmic decay rate of the polyethylene terephthalate sheet (thickness = 25 μm) alone under the same conditions is shown in FIG.
As apparent from FIGS. 8 and 9, in the range of 23 to 180 ° C., the polyethylene terephthalate sheet alone increases the logarithmic decay rate, whereas the ultrathin protective film carrying the adhesive layer has a logarithmic decay rate of The rise was suppressed.

Example 2
(1) Manufacture of printed circuit board As a protective film, the same film as that of Example 1 (1) except that a polyethylene terephthalate sheet support having a thickness of 50 μm and an adhesive layer having a thickness of 2 μm is used. A printed circuit board was manufactured by the operation. The yield of the printed circuit board was 100%.

(2) Measurement of peel strength of protective film The peel strength of the protective film used in Example 2 (1) was measured by the same operation as in Example 1 (2). The results are shown in Table 1.

(3) Measurement of logarithmic decay rate of protective film The logarithmic decay rate of the protective film used in Example 2 (1) and the logarithmic decay rate of the polyethylene terephthalate sheet alone were obtained by the same operation as in Example 1 (2). It was measured. The results are shown in FIG. 10 (logarithmic decay rate of protective film) and FIG. 11 (logarithmic decay rate of polyethylene terephthalate sheet alone). As apparent from FIGS. 10 and 11, in the range of 130 to 180 ° C., the polyethylene terephthalate sheet alone increases the logarithmic attenuation rate, whereas the ultrathin protective film carrying the adhesive increases the logarithmic attenuation rate. Was suppressed.

<< Comparative Example 1 >>
(1) Manufacture of printed circuit board As a protective film, the same film as Example 1 (1) except that a polyethylene terephthalate sheet support having a thickness of 25 μm and an adhesive layer having a thickness of 30 μm is used. A printed circuit board was manufactured by the operation. The yield of the printed circuit board was 90%.

(2) Measurement of peel strength of protective film The peel strength of the protective film used in Comparative Example 1 (1) was measured by the same operation as in Example 1 (2). The results are shown in Table 1.

(3) Measurement of logarithmic decay rate of protective film The logarithmic decay rate of the protective film used in Comparative Example 1 (1) was measured by the same operation as in Example 1 (2). The results are shown in FIG. 12 (logarithmic decay rate of protective film).
As apparent from FIGS. 12 and 9, in the range of 23 to 180 ° C., the logarithmic decay rate of the protective film far exceeded the logarithmic decay rate of the polyethylene terephthalate sheet alone, and the increase suppressing effect was not exhibited.

  By using the pressure-sensitive adhesive-carrying film of the present invention as a protective film in a method for producing a laminate unit for a printed circuit board, the laminate unit can be produced with a good yield, and further, the printed circuit board can be produced. And a multilayer wiring circuit board can be manufactured with a good yield.

It is typical sectional drawing which shows the process (A)-process (F) of a 1st manufacturing method using this invention film in order. It is typical sectional drawing which shows the process (G)-process (M) of a 1st manufacturing method using this invention film in order. It is typical sectional drawing which shows the process (A)-process (G) of a 2nd manufacturing method using this invention film in order. It is typical sectional drawing which shows the process (A)-process (F) of the manufacturing method of the conventional wiring circuit board in order. It is typical sectional drawing which shows the process (G)-process (J) of the manufacturing method of the conventional wiring circuit board in order. It is typical explanatory drawing of the measuring method of the logarithmic attenuation factor by the rigid pendulum free vibration method. It is a graph which shows the relationship between the amplitude of a pendulum in the measuring method of a logarithmic decay rate, and time passage. It is a graph which shows the result of having measured the logarithmic attenuation factor of the ultra-thin protective film used in Example 1 (1) by the method shown in FIG. It is a graph which shows the result of having measured the logarithmic attenuation factor of the polyethylene terephthalate sheet | seat support body of the ultra-thin protective film used in Example 1 (1) by the method shown in FIG. It is a graph which shows the result of having measured the logarithmic decay rate of the protective film used in Example 2 (1) by the method shown in FIG. It is a graph which shows the result of having measured the logarithmic attenuation factor of the polyethylene terephthalate sheet | seat support body single of the protective film used in Example 2 (1) by the method shown in FIG. It is a graph which shows the result of having measured the logarithmic decay rate of the protective film used by the comparative example 1 (1) by the method shown in FIG.

Explanation of symbols

11, 71 ... bump forming metal layer; 12, 72 ... etching barrier layer;
13, 73 ... metal layer for forming a conductor circuit; 16, 76, 86 ... resist film;
17 ... Pressure-sensitive adhesive-carrying protective film;
18 ... Support; 19 ... Pressure-sensitive adhesive layer; 21, 81 ... Bump precursor;
22, 82 ... portions derived from the etching barrier layer;
23, 24, 83, 84 ... conductor circuit; 27, 87 ... interlayer insulating resin layer;
28, 88 ... bump; 31, 91 ... base substrate;
32, 92 ... bump group carrier; 33, 93 ... laminate unit;
34, 94 ... circuit forming substrate; 35, 95 ... wired circuit board;
74: Metal foil for forming a conductor circuit.

Claims (3)

A film carrying a pressure sensitive adhesive on a support,
(I) The initial peel force after sticking to the metal layer for forming a conductor circuit is 0.05 to 30 N / 25 mm,
(Ii) The peeling force can be reduced to less than 0.05 N / 25 mm after irradiation with active energy rays,
(Iii) The logarithmic decay rate of the pressure-sensitive adhesive-carrying film by the rigid pendulum free vibration method is 200% or less of the logarithmic decay rate of the pressure-sensitive adhesive-carrying film support layer alone. The
(IV) In the temperature range exceeding the glass transition point of the support layer of the pressure-sensitive adhesive-carrying film, the logarithmic decay rate on the pressure-sensitive adhesive layer side of the film carrying the pressure-sensitive adhesive layer is Lower than the logarithmic decay rate of
(V) The support layer of the pressure-sensitive adhesive-carrying film is a polyethylene terephthalate film having a thickness of 10 to 100 μm,
(Vi) A pressure-sensitive adhesive-carrying film, wherein the logarithmic decay rate of the pressure-sensitive adhesive-carrying film is 0.005 to 0.07 at 23 to 180C . (1) (a) a metal etching barrier layer, and (b) a first conductor circuit provided on one surface of the etching barrier layer and made of a metal different from the metal constituting the etching barrier layer. A base substrate comprising: a forming metal layer; and (c) a bump forming metal layer provided on the other surface of the etching barrier layer and made of a metal different from the metal constituting the etching barrier layer. In contrast, a step of attaching a pressure-sensitive adhesive-carrying protective film to the surface of the first conductor circuit forming metal layer via the pressure-sensitive adhesive,
(2) In the base substrate, a step of forming a metal bump group by selective etching of the bump forming metal layer to obtain a bump group carrier;
(3) inserting an interlayer insulating resin layer in a state where the top of each bump is exposed in the gap between the bump groups in the bump group carrier; and
(4) The process of peeling the said protective film from the said metal layer surface for conductor circuit formation, after reducing the adhesive force of the pressure sensitive adhesive of the said protective film by active energy ray irradiation
The pressure-sensitive adhesive-carrying film according to claim 1, wherein the pressure-sensitive adhesive-carrying film is used as the pressure-sensitive adhesive-carrying protective film. (1) (a) a metal etching barrier layer, and (b) a first conductor circuit provided on one surface of the etching barrier layer and made of a metal different from the metal constituting the etching barrier layer. A base substrate comprising: a forming metal layer; and (c) a bump forming metal layer provided on the other surface of the etching barrier layer and made of a metal different from the metal constituting the etching barrier layer. In contrast, a step of attaching a pressure-sensitive adhesive-carrying protective film to the surface of the first conductor circuit forming metal layer via the pressure-sensitive adhesive,
(2) In the base substrate, a step of forming a metal bump group by selective etching of the bump forming metal layer to obtain a bump group carrier;
(3) inserting an interlayer insulating resin layer in a state where the top of each bump is exposed in the gap between the bump groups in the bump group carrier; and
(4) The process of peeling the said protective film from the said metal layer surface for conductor circuit formation, after reducing the adhesive force of the pressure sensitive adhesive of the said protective film by active energy ray irradiation
A method of manufacturing a laminate unit for a printed circuit board, comprising:
As the pressure-sensitive adhesive-carrying protective film,
(I) The initial peeling force after sticking to the first conductor circuit forming metal layer is 0.05 to 30 N / 25 mm,
(Ii) The peeling force can be reduced to less than 0.05 N / 25 mm after irradiation with active energy rays,
(Iii) The logarithmic decay rate of the pressure-sensitive adhesive-carrying protective film on the pressure-sensitive adhesive layer side by the rigid pendulum free vibration method is 200% of the logarithmic decay rate of the support layer alone of the pressure-sensitive adhesive-carrying protective film. And
(IV) In the temperature range exceeding the glass transition point of the support layer of the pressure-sensitive adhesive-carrying protective film, the logarithmic decay rate of the pressure-sensitive adhesive layer side of the protective film carrying the pressure-sensitive adhesive layer is Lower than the logarithmic decay rate of the layer alone,
(V) The support layer of the pressure-sensitive adhesive-carrying protective film is a polyethylene terephthalate film having a thickness of 10 to 100 μm,
(Vi) The logarithmic decay rate of the pressure-sensitive adhesive-carrying protective film is 0.005 to 0.07 at 23 to 180 ° C.
Use pressure-sensitive adhesive-carrying protective film
A method for producing a laminate unit for a printed circuit board, wherein:

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